For production of a trifluoromethylthiomethylbenzene derivative, there have been known, for example,
(1) a method of reacting a benzylmercaptan derivative or a benzyl thiocyanate derivative with sodium or potassium trifluoroacetate (JP-A-8-319251),
(2) a method of reacting said derivative with trifluoromethyltrimethylsilane [Tetrahedron Letters, (1997) 38, 65),
(3) a method of reacting said derivative with iodinated or brominated trifluoromethane and zinc (European Patents EP-742202 and EP-247953),
(4) a method of reacting a benzyl halide derivative with a trifluoromethane thiol copper complex [Chem. Ber., (1988) 121, 1833; J. Org. Chem., (1976) 41, 1644],
(5) a method of reacting a benzyl halide derivative with trifluoromethanesulfenyl chloride (U.S. Pat. No. 3,347,765), and
(6) a method of reacting a benzyl halide derivative with bistrifluoromethane disulfide (Synthesis, 1994, 145).
In the method (1), however, the selectivity of intended substance is low and it is difficult to produce a trifluoromethylthiomethylbenzene derivative at a satisfactory yield; in the methods (2) to (4) which use a reagent made from a trifluoromethyl halide (flon) as basic raw material which is an ozone layer-destructing substance and an global-warming gas, the reagent is not suitable industrially because the raw material thereof is difficult to procure in recent years; in the methods (5) and (6), the reagent has a high toxicity and is difficult to procure industrially. Thus, the methods (1) to (6) have had various difficulties in industrial production of trifluoromethylthiomethylbenzene derivative.
The present invention has a main object of providing a process which can produce a trifluoromethylthiomethylbenzene derivative industrially at a high yield at a high purity without using a flon which is an ozone layer-destructing substance and an global-warming gas.